SciHawks

Bio- we discussed the three lines/layers of immune defense against pathogens; the first line of defense consists of your skin and certain fluids that are secreted such as tears and saliva.
If viruses, bacteria, or foreign/harmful proteins get into your blood stream or intercellular fluid via some kind of cut or puncture, you have a second line of defense to prevent proliferation/growth of the pathogens; this second line consists of a general response to the site of infection: increased circulation to bring platelets, clotting factors, interferon, complement, histamines, and macrophages rapidly to the infection site. These parts of the second line of defense are NOT specific so they will generally fight any type of pathogen.
A third line of defense will also be triggered to attack SPECIFIC-shaped antigens on an invading pathogen (especially if that specific pathogen has previously invaded the body). This pathogen-specific line of defense is active in TWO ways: CELLULAR immunity develops as "killer-T" cells are made to specifically attack and break down the invading pathogen; ANTIBODY immunity develops as "B-cells" produces thousands and thousands of specific-shaped proteins called ANTIBODIES that bind ONLY to the specific ANTIGEN-proteins of the invading pathogen. These antibodies are tailor made to have a MATCHING SHAPE so that they only bind to the antigens of the specific invading pathogen. Thus, the antibodies "mark for death/breakdown" the specific invading pathogen (virus/bacteria/fungus/toxin).

Chem 7- we continued to draw out the structures and name members of the following homologous series: alkanes, alkenes, and alkynes. For alkenes and alkynes, you must find the longest consecutive carbon chain that CONTAINS/HAS the double or triple bond, respectively.
Then, you number the carbon chain so that the double or triple bond is BETWEEN the LOWER(/EST) number carbons.
We then looked at the series of organic compounds that contain one or more halogen atoms: the ALKYL HALIDES. Generally, you number the carbon chain of any SATURATED (ALL single bonds) alkyl halide so that the halogen atoms are on the lowest number carbon.
Remember to use the prefixes, di-, tri-, etc. any time that there is more than one of the same halogen or even alkyl group (e.g. dimethyl for two CH3 groups on the side).
We then continued with one of several different types of organic molecules that can be recognized based on its FUNCTIONAL GROUP. We looked at alCOHols, that all have a hydroxy (OH) functional group covalently bonded to the carbon chain.
We saw that each alcohol has the suffix "ol" in its name. The rest of the name is generally determined by taking the first two syllables of its "alkane"carbon-skeleton name. So, a two carbon alcohol is called ETHANol.
We defined primary, secondary, and tertiary alcohols and then we discussed monohydroxy (ONE OH per molecule), DIhydroxy (TWO OH groups per molecule), and TRIhydroxy (THREE OH groups per molecule) alcohols. DO NOT CONFUSE dihydroxy alcohols with SECONDARY alcohols! Secondary alcohols are ALWAYS monohydroxy alcohols that have the OH group on a SECONDARY carbon, i.e. a carbon that is bonded to TWO other carbons.



Chem 8/9- we continued to draw out the structures and name members of the following homologous series: alkanes, alkenes, and alkynes. For alkenes and alkynes, you must find the longest consecutive carbon chain that CONTAINS/HAS the double or triple bond, respectively.
Then, you number the carbon chain so that the double or triple bond is BETWEEN the LOWER(/EST) number carbons.
We then looked at the series of organic compounds that contain one or more halogen atoms: the ALKYL HALIDES. Generally, you number the carbon chain of any SATURATED (ALL single bonds) alkyl halide so that the halogen atoms are on the lowest number carbon.
Remember to use the prefixes, di-, tri-, etc. any time that there is more than one of the same halogen or even alkyl group (e.g. dimethyl for two CH3 groups on the side).

We then did a lab activity using molecular models to make the FIVE possible isomers of C6H14.

Bio- HW: due Monday, outline text section 39.1
We began our discussion of the Immune System by looking at causes of infectious, hereditary, and environmental/behavioral diseases.
We defined the term, pathogen, which is any agent that causes an infectious disease: virus, bacterium, fungus, protist, etc.
We discussed several means by which pathogens can spread infection throughout a population and
how some pathogens are more virulent or less fragile than others.
We also began to discuss the human organism's three lines of defense against pathogens.

Chem 7/8- we continued our unit on Organic Chemistry by looking at the various HOMOLOGOUS SERIES of hydrocarbons: the alkanes (all single bonds, saturated with H) , alkenes (contain ONE double bond), and alkynes (contain ONE triple bond; "alkYne-trYple"). We looked at the GENERAL FORMULA of each of the homologous series of hydrocarbons and noted that, for each additional multiple bond, TWO fewer H's are in the formula.
We also practiced naming each successive member of a homologous series and the possible isomers for a given chemical formula.
We also began another series of organic compounds, alkyl halides, each of which contains one or more halogen atoms covalently bonded to the carbon chain. We saw that the naming rules for alkyl halides are similar to those for naming alkanes with side chains.

We then did an activity in which we built models of all possible isomers of C6H14.

Chem 9- we continued our unit on Organic Chemistry by looking at the various HOMOLOGOUS SERIES of hydrocarbons: the alkanes (all single bonds, saturated with H) , alkenes (contain ONE double bond), and alkynes (contain ONE triple bond; "alkYne-trYple"). We looked at the GENERAL FORMULA of each of the homologous series of hydrocarbons and noted that, for each additional multiple bond, TWO fewer H's are in the formula.
We also practiced naming each successive member of a homologous series and the possible isomers for a given chemical formula.

Bio- we took our unit exam and then continued our discussion of the "Making Connections"/Proper Experimental Design Lab, which reinforces your knowledge of using science to:
1. answer questions/ resolve disputes about natural phenomena
2. find the possible relationship or lack thereof between two variables.

Our next unit is a GREAT one: the Immune System.
Outlines will be assigned for Chapter 39 of the text.

Chem 7- we finished our overview/review of intermolecular attractions, noting the multi-step process that is involved in PROVING (not guessing) that a given molecule will have stronger intermolecular attractions, which leads to its higher boiling point, than another molecule. You must draw the Lewis structure, from which one can find the molecular SHAPE and, when considered along with the polarity of the bonds and the lone pairs of electrons, you can determine the molecular polarity or lack thereof. You can then infer the type and strength of the intermolecular attractions BETWEEN the molecules that must be OVERCOME (no BONDS are broken!) in order to separate the molecules into the gas phase (boiling).
We then began our new unit for the 3rd quarter: OrganiC(H) Chemistry.
We noted that ALL organic compounds have AT LEAST one Carbon AND at least one Hydrogen atom PER molecule. That is why carbon dioxide does NOT qualify/is NOT categorized as an organic molecule.
We defined the term ISOMER, which is a compound having the same chemical formula as another compound BUT having a DIFFERENT arrangement of atoms and/or bonds. For example, you will see that there are THREE different molecules that have the formula C5H12; each one is an isomer of the other two.
We began to look at homologous series of HYDROCARBONS, molecules that consist of ONLY carbon and hydrogen (and NO OTHER element).
We looked at the general formulas of alkAnes, alkEnes, and alkYnes. All alkanes have only SINGLE bonds (SATURATED with H), all alkenes have ONE double bond, and all alkynes have ONE triple bond somewhere in the molecule.

Chem 8/9- we reviewed intermolecular attractions, noting the multi-step process that is involved in PROVING (not guessing) that a given molecule will have stronger intermolecular attractions, which leads to its higher boiling point, than another molecule. You must draw the Lewis structure, from which one can find the molecular SHAPE and, when considered along with the polarity of the bonds and the lone pairs of electrons, you can determine the molecular polarity or lack thereof. You can then infer the type and strength of the intermolecular attractions BETWEEN the molecules that must be OVERCOME (no BONDS are broken!) in order to separate the molecules into the gas phase (boiling).
We then began our new unit for the 3rd quarter: OrganiC(H) Chemistry.
We noted that ALL organic compounds have AT LEAST one Carbon AND at least one Hydrogen atom PER molecule. That is why carbon dioxide does NOT qualify/is NOT categorized as an organic molecule.
We defined the term ISOMER, which is a compound having the same chemical formula as another compound BUT having a DIFFERENT arrangement of atoms and/or bonds. For example, you will see that there are THREE different molecules that have the formula C5H12; each one is an isomer of the other two.
We began to look at homologous series of HYDROCARBONS, molecules that consist of ONLY carbon and hydrogen (and NO OTHER element).
We looked at the general formulas of alkAnes, alkEnes, and alkYnes. All alkanes have only SINGLE bonds (SATURATED with H), all alkenes have ONE double bond, and all alkynes have ONE triple bond somewhere in the molecule.

Bio- we reviewed for tomorrow's extensive exam on the circulatory, respiratory, and excretory systems. Make sure that you know the structures and functions of each system, the diseases or disorders of each system, and the "INTER-connectedness" the three systems, that is, how the systems interact to maintain homeostasis within the body.
Keep writing and re-writing the review sheet questions and answers (posted on Blackboard) until you know them thoroughly, review the worksheets, your outlines, and, especially, the notes.

Chem 7/8- we took the multiple choice part of the quarterly exam.
We then reviewed some of the major differences between intermolecular ATTRACTIONS and true covalent bonds and which of these factors apply when determining relative boiling points.
Check your grades for completeness; if there is a missing or inaccurate grade, bring in the assignment that I did not record BEFORE tomorrow afternoon.

Chem 9- we took the multiple choice part of the quarterly exam. Check your grades for completeness; if there is a missing grade, bring in the assignment that I did not record BEFORE tomorrow afternoon.
Check your grades for completeness; if there is a missing or inaccurate grade, bring in the assignment that I did not record BEFORE tomorrow afternoon.

For Monday's exam, in addition to all material from the second quarter, make sure that you do some problems/review the following types of problems:

1. gas law calculations involving changes in P, V, and/or T (practice using the formulas that are on the Reference Tables); all of the old worksheets and answers are still on Blackboard!
2. heating and cooling curve calculations of heat of fusion, heat of vaporization, and
q(heat) = m c "delta"T calculations (formulas are on the Reference Tables); all of the old worksheets and answers are still on Blackboard!

Also, from the Atomic Structure unit, you are responsible for knowing the quantum mechanical model of the atom including s,p,d,f electron configurations and orbital notations.

Be prepared so that you can use this opportunity to increase your understanding and improve your grade.

Bio- we finished our discussion of the excretory system by focusing on the structure and function of the urinary system. The urinary system is composed of the kidneys, the two URETERS (remember uddERs) through which urine flows from the kidneys to the urinary bladder; the bladder temporarily holds the urine until the bladder fills and then the urine is excreted through the single tube, the URETHRA.

We worked on a handout to reinforce that material; the answers to the handouts are posted on Blackboard so check your work.

We performed the experiment in our "Making Connections" lab. The results, if consistently seen with REPEATED trials AND a LARGE sample size would enable us to have a scientifically supported opinion (the only opinion that has objective meaning) on whether warming up/exercising before the specific "squeezing" exercise contributes more towards muscle fatigue than not exercising first.

We begin our 3rd quarter on Monday; let us take time to think about what we've learned in Biology so far this year, what habits are helpful in learning this subject well, and what we can do to avoid habits that have been detrimental/harmful.

Chem 7- we took the written-response part of the second quarter exam; I am grading those over the weekend.
So far so good, though some of you need to look at the notes regarding the HUGE difference between a BOND (ionic or covalent) and a mere INTERMOLECULAR ATTRACTION.
BONDS of ANY KIND are over a THOUSAND TIMES stronger than ANY intermolecular attraction.
That is why, when you boil ANY molecular liquid, you merely can get the molecules to OVERCOME their INTERMOLECULAR attractions but NEVER do you break ANY of the bonds WITHIN the molecule, i.e. when you boil water, you STILL have covalently BONDED H2O in the gas phase; you've merely separated the various water molecules by giving them enough energy to overcome their extreme dipole-dipole attractions (called hydrogen "bonding"- which is NOT a bond because no electrons are shared BETWEEN separate molecules). If I have any updates/emphases about Monday's exam, I'll post them here and on Blackboard by Sunday.

Chem 8/9- we took the written-response part of the second quarter exam; I am grading those over the weekend.
So far so good, though some of you need to look at the notes regarding the HUGE difference between a BOND (ionic or covalent) and a mere INTERMOLECULAR ATTRACTION.
BONDS of ANY KIND are over a THOUSAND TIMES stronger than ANY intermolecular attraction.
That is why, when you boil ANY molecular liquid, you merely can get the molecules to OVERCOME their INTERMOLECULAR attractions but NEVER do you break ANY of the bonds WITHIN the molecule, i.e. when you boil water, you STILL have covalently BONDED H2O in the gas phase; you've merely separated the various water molecules by giving them enough energy to overcome their extreme dipole-dipole attractions (called hydrogen "bonding"- which is NOT a bond because no electrons are shared BETWEEN separate molecules).

We then played some compound naming Jeopardy. If I have any updates/emphases about Monday's exam, I'll post them here and on Blackboard by Sunday.

Bio- HW outline of section 37.3 is due on Friday.
Because of the Math A Regents, we just did general test skills practice; check Blackboard for the annotated questions and answers.

Chem 7/8- we had extensive review of much of the relevant material on tomorrow's test. However, this is a quarterly exam so anything from the second quarter notes and even some material from the first quarter (especially that which was highlighted in today's review) can be on part I or part II of the test. Be prepared.
On Blackboard, I posted my fully annotated questions and answers for the quarterly review packet. If you are taking your tests properly, your test will look just like that review packet. The underlined keywords, predicted answers, and illustrations prevent careless errors and almost guarantee that you will answer correctly and confidently.

Chem 9- I didn't get to the TWO main errors that I saw in most of the homeworks. Do not repeat these errors on the quarterly:
1) there is no such thing as FLOURine! Fluorine is the element.
Mnemonic: FLUorine has the FLU! Get it right for good.
2) Whenever you write a transition metal in ANY compound, the name MUST (not optional!!!) have a Roman numeral/Stock system designation, which tell which of the two or three possible ions OF that metal is in the compound. So, iron oxide is WRONG but iron II oxide refers to FeO whereas iron III oxide refers to a different salt, Fe2O3 .
Practice your formula writing of these salts in particular.

we reviewed much of the relevant material for tomorrow's exam though we did not have time for drawing Lewis structures of molecules, physical properties of molecules vs. metals vs. salts vs. network solids. Use your notes and previous tests and review packets to study for that.
On Blackboard, I posted my fully annotated questions and answers for the quarterly review packet. If you are taking your tests properly, your test will look just like that review packet. The underlined keywords, predicted answers, and illustrations prevent careless errors and almost guarantee that you will answer correctly and confidently.

Bio- HW: Outline section 37.3 is due on FRIDAY.
we recapped our discussion of the respiratory system by looking at some animations. We focused on the exchange of oxygen and carbon dioxide in the alveoli and surrounding capillaries. We also saw an animation that explained the mechanics of breathing in terms of diaphragm contractions that cause air pressure differences between the chest (thoracic) cavity and the environment.
I'll post those videos on Blackboard for your review.
We also began the excretory system by noting the organs that serve several purposes but that are also involved in excretion:
the skin- necessary for regulation (temperature and water balance) but also functions in excretion by ridding the body of excess water, salts, and urea.
the liver- has a digestive/nutrition function (secreting bile) and a regulation function (converting glycogen to glucose and vice-versa); its excretory function is to detoxify the blood and to form urea from the breakdown of amino acids, the urea is then excreted via the skin and the kidneys.
the lungs- naturally are the main part of the respiratory system but the lungs are simultaneously excreting carbon dioxide, a metabolic waste, from the body.

We then focused on the main organ or the urinary system, which is one of the main systems used in excretion. We looked at the illustration of its parts: the kidneys, the ureters, the urinary bladder, and the urethra. We will go into further detail on that tomorrow.

We continued with the NY State "Making Connections" Lab by discussing the aspects of a valid scientific experiment/study that can be used to resolve differences of opinion about natural phenomena. Specifically, you designed an experiment that will determine whether exercising before a particular exercise will increase or decrease the level of muscle fatigue. We will continue that on Friday.

Chem 7- NOTE! Due to the Math A Regents, our class tomorrow (THURSDAY) will be held in Room 243! Do not go to Room 307 on Thursday.
Today, we reviewed the prefix vs. the Stock system for naming molecules.
We then focused on determining the oxidation numbers/states of each atom in a polyatomic ion and in a salt of a polyatomic ion. We saw that, the oxidation numbers of the atoms within the polyatomic stay the same, whether the polyatomic ion is part of a salt lattice or just by itself (in solution).
Beware, correctly naming compounds takes a lot of practice! The quarterly exam is on Friday and Monday. You need to do many (at least 10 of EACH type of compound) naming problems in order to be competent on the test.
We then showed how to determine the number of "atoms" (sometimes a combo of atoms AND ions) in each "formula unit" of a compound.

Chem 8/9 - NOTE! Due to the Math A Regents, our class tomorrow (THURSDAY) will be held in Room 243! Do not go to Room 307 on Thursday.
Today, we reviewed the prefix vs. the Stock system for naming molecules.
We then focused on determining the oxidation numbers/states of each atom in a polyatomic ion and in a salt of a polyatomic ion. We saw that, the oxidation numbers of the atoms within the polyatomic stay the same, whether the polyatomic ion is part of a salt lattice or just by itself (in solution).
We briefly discussed the outdated "ic" vs. "ous" system for naming salts of transition metals; this system is neither on the Regents exam nor on the quarterly exam.
Beware, correctly naming compounds takes a lot of practice! The quarterly exam is on Friday and Monday. You need to do many (at least 10 of EACH type of compound) naming problems in order to be competent on the test.
We then showed how to determine the number of "atoms" (sometimes a combo of atoms AND ions) in each "formula unit" of a compound.
We finished our discussion of the molecular model lab and handed that in.

Bio- we finished our discussion of the respiratory system by focusing on the breathing mechanism:
the medulla oblongata of the brain detects a slight increase in CO2 in the blood, causing the medulla to send a chemical signal to the diaphragm. The diaphragm contracts DOWNWARD and the rib cage widens a little which causes the chest cavity to expand, which LOWERS the air pressure inside the lungs. That causes air to rush in from the higher air pressure surroundings. The diaphragm the relaxes and the rib cage returns to its unexpanded position causing the chest cavity volume to decrease, which increases the air pressure in the lungs. This now higher pressure air is forced out of the lungs to the lower air pressure surroundings. Then, the cycle repeats usually about 15 times per minute. So, overall, this is how oxygen is delivered to the alveoli in the lungs where it then diffuses into the pulmonary capillaries and carbon dioxide diffuses from the capillaries into the alveoli. The carbon dioxide is then excreted as you exhale.
We also discussed certain diseases of the respiratory system such as bronchitis, pneumonia, emphysema, and lung cancer.

Chem 7/8- NOTE: on the hw packet, I will not be grading the section on "oxidation numbers of the atoms within the polyatomic ion" because we did not get to that yet. Also, for ANY binary (two element) ionic compound/salt, the oxidation number of the metal is the SAME as its ionic charge e.g. Fe 2+ has an oxidation number of +2 and the oxidation number of the nonmetal is the SAME as its ionic charge e.g. P 3- has an oxidation number of -3; so that doesn't require any extra work or computation.
We continued our practice of naming salts and molecules. We practiced with salts of polyatomic ions noting that for any compound that has an empirical formula (formula unit) with more than one polyatomic ion, that ion must be in parentheses... e.g. Ca(NO3)2 However, if there is only one of the polyatomic ion in the empirical formula (formula unit), then you CANNOT use parentheses...e.g NaNO3
We discussed the STOCK SYSTEM for molecules with which me must use "OXIDATION NUMBERS" for the nonmetals in the molecule. You must consider ONLY the second element in the formula FIRST. That element is your anchor and it is GUARANTEED that atoms of that particular element have their most NEGATIVE (topmost!) oxidation number. Then, from the rest of the formula, you must make the oxidation numbers BALANCE in the same way that you make TRUE IONIC CHARGES balance in salts. The oxidation number of the FIRST (less electronegative) element in the molecule is then written as a ROMAN NUMERAL after the element's name in the formula followed by the second element's truncated name with "ide" as a suffix: that means, for example, CO2 is carbon IV oxide because O is almost always -2 and there are two O's in the molecule, the one C must have a +4 oxidation number.

We then briefly discussed the old-school "ous" vs. "ic" suffixes for salts of transition metals.
We finished our molecular model discussion noting the universal truth that ALL trigonal pyramid and V-shaped molecules MUST BE polar due to their asymmetric charge distribution.

Chem 9- NOTE: on the hw packet, I will not be grading the section on "oxidation numbers of the atoms within the polyatomic ion" because we did not get to that yet. Also, for ANY binary (two element) ionic compound/salt, the oxidation number of the metal is the SAME as its ionic charge e.g. Fe 2+ has an oxidation number of +2 and the oxidation number of the nonmetal is the SAME as its ionic charge e.g. P 3- has an oxidation number of -3; so that doesn't require any extra work or computation.
We continued our practice of naming salts and molecules. We practiced with salts of polyatomic ions noting that for any compound that has an empirical formula (formula unit) with more than one polyatomic ion, that ion must be in parentheses... e.g. Ca(NO3)2 However, if there is only one of the polyatomic ion in the empirical formula (formula unit), then you CANNOT use parentheses...e.g NaNO3
We discussed the STOCK SYSTEM for molecules with which me must use "OXIDATION NUMBERS" for the nonmetals in the molecule. You must consider ONLY the second element in the formula FIRST. That element is your anchor and it is GUARANTEED that atoms of that particular element have their most NEGATIVE (topmost!) oxidation number. Then, from the rest of the formula, you must make the oxidation numbers BALANCE in the same way that you make TRUE IONIC CHARGES balance in salts. The oxidation number of the FIRST (less electronegative) element in the molecule is then written as a ROMAN NUMERAL after the element's name in the formula followed by the second element's truncated name with "ide" as a suffix: that means, for example, CO2 is carbon IV oxide because O is almost always -2 and there are two O's in the molecule, the one C must have a +4 oxidation number.

Bio- Outline HW: Section 37.1 is due Wednesday and Section 37.3 is due on Friday. Our NEXT UNIT TEST is on TUESDAY, JANUARY 29th (not next Friday, good thing!).
we finished the circulatory system by discussing the "fluid" that is pumped through the vessels by the heart; that fluid is the blood, which is composed of red blood cells (erythrocytes), white blood cells, platelets, and plasma. Blood is the connective tissue that links all parts of the body.
The red blood cells, which contain no nucleus, transport oxygen to body cells from the lungs and transport carbon dioxide from body cells to be excreted by the lungs.
There are several different specific white blood cells, but they all are involved in your immune system, helping your body to maintain homeostasis by preventing harmful substances, cells, or organisms from entering or affecting your body.
The platelets help to form blood clots to prevent bleeding from broken blood vessels; you have a CLOSED circulatory system so all of the blood is ENCLOSED within vessels that must remain free from holes or punctures to contain the blood; platelets aid in plugging up any breaches in these vessels.
The plasma contains dissolved and undissolved (mixed) enzymes, vitamins, minerals, sugars, fatty acids, amino acids, hormones, nucleotides that are transported to the various cells of the body.

We then began our focus on the system that works in cooperation with the circulatory system:
the RESPIRATORY system.
We recalled the two types of CELLULAR respiration: aerobic and anaerobic.
The oxygen needed by cells (mitochondria) for aerobic respiration is obtained by the functioning of the respiratory system and transported to the cells via the circulatory system.
We labeled the parts and functions of the various components of the respiratory system and we will discuss how the lungs expand and contract via the diaphragm muscle.

We began our "Making Connections" lab by taking our resting pulses (which is a measure of your heart muscle/ventricle contraction rate) and averaging those pulses over three trials.
I have posted our results via a Google Spreadsheet linked here.
I'll also post the histogram/chart of our data and all of the worksheets and answers (do your work first, of course) on Blackboard this weekend (probably by Saturday night).

Chem 7- Here is a link to some great compound-naming tutorials complete with practice question sets and answers.
Apologies for that monster formula-naming handout; that was supposed to be printed with an answer key but, to my displeasure, I was alerted by Chem 9th that the 345 formulas were just REPEATED without answers. Uggh. Gggaaahgd!
So, to remedy the situation, IGNORE that handout, please. I WILL post legitimate inorganic compound-naming worksheets WITH answer keys on Blackboard. Some of the problems on the worksheets are for later units (acids, hydrated salts) so I encoded those problems in RED FONT; ignore those particular problems.
We reviewed naming salts of representative metals, transition, and polyatomic ions. We also practiced naming molecules via the PREFIX system (mono, di, tri).
Remember, if you get stuck, never forget how you name the MOLECULES carbon dioxide and carbon monoxide; also remember how you name table SALT: sodium chloride. Those examples as models/templates, prefixes for molecules, NO prefixes for salts, should help you name many molecules and salts.
You should also know that you CANNOT tell the formula of a salt from its name! That's right! For example, aluminum oxide is NOT AlO. It is Al2O3 due to the charges of the aluminum and oxide ions; in the lattice of ions, there are TWO Al (3+) cations for every THREE O (2-) ions so that the charges balance.
You CAN tell the formula of a molecule from its prefix system name, though.

Our QUARTERLY exam is next Friday. There is a HUGE review question packet on Blackboard under the "Review Materials" link. Download that file and do the questions early and often so that you can ask me about anything that you are not totally sure about.


Chem 8/9- Here is a link to some great compound-naming tutorials complete with practice question sets and answers.
Thanks for the heads-up about the formula-naming worksheet today. Don't bother with that handout, please. I WILL post legitimate inorganic compound-naming worksheets WITH answer keys on Blackboard tonight or tomorrow. Some of the problems on the worksheets are for later units (acids, hydrated salts) so I encoded those problems in RED FONT; ignore those particular problems.
We reviewed naming salts of representative metals, transition, and polyatomic ions. We also practiced naming molecules via the PREFIX system (mono, di, tri).
Remember, if you get stuck, never forget how you name the MOLECULES carbon dioxide and carbon monoxide; also remember how you name table SALT: sodium chloride. Those examples as models/templates, prefixes for molecules, NO prefixes for salts, should help you name many molecules and salts.
You should also know that you CANNOT tell the formula of a salt from its name! That's right! For example, aluminum oxide is NOT AlO. It is Al2O3 due to the charges of the aluminum and oxide ions; in the lattice of ions, there are TWO Al (3+) cations for every THREE O (2-) ions so that the charges balance.
You CAN tell the formula of a molecule from its prefix system name, though.

We almost put the molecular model lab to bed today but we will quickly finish that on Wednesday.

Our QUARTERLY exam is next Friday. There is a HUGE review question packet on Blackboard under the "Review Materials" link. Download that file and do the questions early and often so that you can ask me about anything that you are not totally sure about.

Bio- we went over test-taking skills as applied to our last test. Try to learn from your past mistakes so that you can warn yourself before the next test about how to take a test properly to maximize your score.
We discussed some of the common diseases of the cardiovascular system.
Hypertension, which is high blood pressure, can have many independent and cumulative causes such as stress, genetics/heredity, diet, and substance abuse.
Recall the first measurement of a blood pressure reading is the systolic (SQUEEZE) pressure (typically 100 to 150 mmHg) and the second measurement is the diastolic pressure (when the heart is "relaxed" as blood goes from the atria to the ventricles (not a high-force contraction).

We discussed two similar heart attack- causing conditions:
1. coronary thrombosis, in which a thrombus- a mass of cholesterol or a blood clot particle- attaches to some plaque on the inside of a coronary artery causing a blockage of the artery.
The red blood cells are then blocked from delivering oxygen to certain heart cells and a heart attack may ensue.

2. angina pectoris is the NARROWING of coronary arteries due to deposits of cholesterol or some other plaques on the inner walls of the arteries. This causes an insufficient number of red blood cells to deliver oxygen to certain heart muscle cells.

We will discuss two other disorders after we talk about the "fluid" of the circulatory system: the blood.

Chem 7/8: we revisited the proper naming of ionic compounds (salts and bases) and covalent compounds/molecules.
We discussed the MEANING of a chemical formulas; ionic compound formulas have a DIFFERENT meaning than covalent molecule formulas because ionic formulas only tell you the RATIO of metal cations to nonmetal anions in the LATTICE (or solution) of the salt.
Molecular formulas tell you the EXACT number of atoms of each element in a SINGLE molecule of the compound or element.
We noted that ionic compounds of transition metals REQUIRE a Roman numeral whenever there is the possibility of more than one charge of metal cation for that element (that IS the case for MOST transition metals); otherwise a Roman numeral CANNOT be used.

We then discussed and completed our electrolyte/conductivity lab and most of our molecular model lab.

Chem 9: we revisited the proper naming of ionic compounds (salts and bases) and covalent compounds/molecules.
We discussed the MEANING of a chemical formulas; ionic compound formulas have a DIFFERENT meaning than covalent molecule formulas because ionic formulas only tell you the RATIO of metal cations to nonmetal anions in the LATTICE (or solution) of the salt.
Molecular formulas tell you the EXACT number of atoms of each element in a SINGLE molecule of the compound or element.

Bio- HW: have tests signed by parent/guardian and return the tests to me tomorrow. Text Section 37.2 outline (except for the subsection on "ABO Blood Groups") is due on Thursday.

We described and illustrated the structure and function of the heart. We noted that the heart has four chambers: two atria and two ventricles. We described the heart's pumping action: the two atria simultaneously beat, sending deoxygenated blood from the right atrium through the open right A-V valve to the right ventricle just below it while sending freshly oxygenated blood from the left atrium to the left ventricle. Then, in about one second, the two ventricles simultaneously contract, sending deoxygenated blood from the right ventricle to the lungs via the pulmonary arteries while oxygenated blood gets pumped from the left ventricle to the aorta.

The heartbeat that is heard ("lub-dub" sound) is the result of the A-V valves slamming shut to avoid backflow of blood from ventricles to atria after the atria have contracted ("lub") and then the "semilunar"/mitral valves strongly slamming shut ("dub") to avoid backflow of blood from aorta to left ventricle or from pulmonary arteries to right ventricle after the ventricles have contracted.

We discussed the three types/regions of blood circulation, each with a particular purpose:

systemic circulation: the most far-reaching circulation of blood throughout the body from the heart to aorta to arteries, arterioles, capillaries, venules, veins and back to the heart.

coronary circulation: the sending of blood FROM the heart TO the heart via coronary arteries; blockage of these arteries causes a heart attack.

pulmonary (lung) circulation: the transport of blood from heart to lungs and back to the heart so that oxygen can diffuse from the lungs to the red blood cells and that carbon dioxide can be released from the blood cells and diffuse into the lungs.

Chem 7- IMPORTANT: start studying for next Friday's quarterly exam. There is an EXTENSIVE review question packet on Blackboard filed in the "REVIEW MATERIALS" link. That test will be your last chance to increase your quarterly average.

we took the all-important Bonding/IMFA test today; the first three tests that I glanced at while walking around the class ALL contained the errors FOREWARNED about in the post from Monday and which I also carefully and explicitly warned the class about during review yesterday. It really pays to heed the test advice.

Chem 8/9:
IMPORTANT: start studying for next Friday's quarterly exam. There is an EXTENSIVE review question packet on Blackboard filed in the "REVIEW MATERIALS" link. That test will be your last chance to improve your quarterly average.

we took the all-important Bonding/IMFA test today. Some of you did not heed the warning from Monday's blog-post and from yesterday's review lesson. It really pays to heed the test advice.

We continued our writeup of the conductivity lab. We will complete that and the molecular model lab writeup quickly on Friday.

Bio- HW due Thursday- outline Section 37.2 (except for the part on ABO Blood Groups)
we began our new unit by discussing the circulatory system, which is composed of blood (the transport fluid), the heart (the pump), and the blood vessels (network through which the blood is transported).
We described the structures and functions of arteries, arterioles, capillaries, venules, and veins.
We then began to discuss the mechanism of the heart.

Chem 7/8: tomorrow is our Bonding/Intermolecular Attractions test, which is THE most important test in chemistry. It encompasses knowledge of atomic structure, periodic properties, as well as an understanding of how a substance's shape and polarity affect its properties.
Much of this topic cannot be memorized but rather must be understood through lots of practice in drawing out molecules, ions, metallic lattices, etc.
I have put additional extra help files on Blackboard.

Today, we covered two last details:
the concept of ionic and covalent "CHARACTER", which just tells how unequal or equal the electrons are shared between nuclei. To get the right answer, just look up the electronegativity difference between the two elements in the substance. The greater the difference, the more unequal the sharing of the electrons, thus, the more ionic (less covalent) the character.
We also discussed compounds that have BOTH ionic and covalent bonding occurring within any sample of the substance: to get that, just find a compound that has a POLYATOMIC ION (see Tables E or F); there are ionic bonds among the IONS BUT covalent bonds WITHIN the polyatomic ion, which is usually made up of covalently bonded nonmetal atoms.
We also saw that aqueous SALT solutions are called "ELECTROLYTES" because they conduct electricity as the CHARGED ions are "swimming" (net movement) through the solution.
Most (all, for now) molecules are nonelectrolytes due to the lack of ions and no net movement of their electrons.
We then discussed our latest lab, which we will hand in on Thursday.
Study intensely and good luck on tomorrow's test.

Chem 9: tomorrow is our Bonding/Intermolecular Attractions test, which is THE most important test in chemistry. It encompasses knowledge of atomic structure, periodic properties, as well as an understanding of how a substance's shape and polarity affect its properties.
Much of this topic cannot be memorized but rather must be understood through lots of practice in drawing out molecules, ions, metallic lattices, etc.
I have put additional extra help files on Blackboard.

Today, we covered two last details:
the concept of ionic and covalent "CHARACTER", which just tells how unequal or equal the electrons are shared between nuclei. To get the right answer, just look up the electronegativity difference between the two elements in the substance. The greater the difference, the more unequal the sharing of the electrons, thus, the more ionic (less covalent) the character.
We also discussed compounds that have BOTH ionic and covalent bonding occurring within any sample of the substance: to get that, just find a compound that has a POLYATOMIC ION (see Tables E or F); there are ionic bonds among the IONS BUT covalent bonds WITHIN the polyatomic ion, which is usually made up of covalently bonded nonmetal atoms.
We also saw that aqueous SALT solutions are called "ELECTROLYTES" because they conduct electricity as the CHARGED ions are "swimming" (net movement) through the solution.
Most (all, for now) molecules are nonelectrolytes due to the lack of ions and no net movement of their electrons.
Study intensely and good luck on tomorrow's test.

I am unpleasantly surprised by some of you. I just went through the homework papers. Many of you did okay (two or three things to review before the test), some did great, but some (at least six) of you are clearly about to FAIL the next test if you do not sit down and study your notes and do practice problems by USING your notes. If you are taking the time to read this, you probably did not make the errors discussed below but, just in case...

Two MAJOR problems that I EXPLICITLY forewarned about:

As you must know by now (just from knowing the structure of table salt, sodium chloride i.e. NaCl), METALS CANNOT EVER COVALENTLY BOND TO NONMETALS. Do not EVER put a DASH between a METAL and a NONMETAL in ANY Lewis Structure. Dashes symbolize COVALENT BONDS. Nonmetals ALWAYS GAIN/STEAL electrons from metals (you know, Zeff!) so IONS MUST FORM and are arranged in a LATTICE. That is the case for EVERY metal-nonmetal compound. ALL Lewis Diagrams of IONS MUST BE IN BRACKETS!!!! THE CHARGE OF THE ION MUST BE WRITTEN, SIGN FIRST, THEN NUMBER, OUTSIDE OF THE BRACKET.
Look at your notes; copy your notes; get comfortable writing correct information. We did MANY examples of Lewis structures for salts/ionic compounds.

Secondly, when you write the formula for a salt, ANY SALT, like NaCl, do so just as you do for sodium chloride. That means, in your FINAL answer, do NOT EVER put + or - signs, charges etc. in the final formula. ALL salts are electrically balanced, like NaCl, which is why we do not write Na + + Cl - as the formula. Yes, those ions exist, but that is NOT how we have ever written any formula (see notes for proof).

For you own sake, DO NOT make those mistakes on Wednesday's test. DO come to extra help; clearly some of you need A LOT of it before Wednesday.
The formula of any salt SHOULD be figured out BEFORE you attempt to draw the Lewis Structures of the ions or else you will waste a LOT of time.
CLEARLY, too many of you are not looking at or using your notes when you do the homework. I read at least 10 papers with IDENTICAL completely wrong answers that do not remotely look like anything from our notes.

Bio - we had our Digestive and Endocrine System exam.
We discussed our Salivary Amylase and Protein Digestion labs, which are posted on Blackboard. You will put those in your lab folders on Wednesday.
Tomorrow, we begin a three-system unit: the Respiratory, Circulatory, and Excretory systems.
We will discuss the major structures within these systems and the function/purpose of each structure in helping the body perform its life processes. We will be gradually outlining chapter 37 of our text for this unit.

Chem 7- we reviewed Van der Waal's/London Dispersion/induced dipole attractions and noted that, though they are relatively the weakest of intermolecular attractions, they can be stronger when molecules:
1. close together (under high pressure)
2. have a lot of electrons (so the induced dipoles are greater and more frequent)

We then explained the fact that all bonds must be significantly stronger (much harder to break) than mere intermolecular attractions because all bonds involve FULLY and oppositely charged particles whereas intermolecular attractions involve ONLY PARTIALLY and oppositely charged regions of different molecules attracting each other.

We looked at the four types of solids and we explained their respective properties.
IONIC: only conduct electricity (via mobile IONS) in the liquid or aqueous phase but NOT in the solid phase (ions NOT mobile in a SOLID). VERY high boiling and melting points due to the STRONG IONIC BONDS that require tremendous energy to OVERCOME.

NETWORK COVALENT: ONLY C (diamond or graphite), Si, SiC, and SiO2. There is no such thing as a single SiO2 molecule! The SiO2 tells you the RATIO of Si to O in the LATTICE of covalently bonded atoms.
No electrical conductivity = no ions and the electrons are NOT mobile; the electrons are stuck between the nuclei in bonds.
HIGH melting and boiling points because COVALENT BONDS are super STRONG and require insane quantities of energy to be broken.

MOLECULAR: e.g. solid H2O, C6H12O6, C12H22O11
solid molecules consist of COMPELETELY SEPARATE MOLECULES THAT ARE NOT BONDED TO EACH OTHER. The only thing holding the SEPARATE molecules frozen in place are INTERMOLECULAR attractions (Vanderwaal's, dipole-dipole, or H-"bonding" attractions).
So, relatively LOW to medium melting and boiling points.
NO electrical conductivity: NO ions and the electrons are stuck between the nuclei in bonds.

METALLIC: e.g. Cu, Ag, K, bronze
HIGH melting and boiling points due to STRONG metallic bonds- multiple positive nuclei attracted to any and all surrounding valence electrons of all surrounding atoms creates tremendous mutual attractions called metallic BONDS.
ELECTRICAL CONDUCTIVITY in both SOLID and LIQUID phases due to mobile ELECTRONS (not ions!), which are weakly attracted to any of the LOW Zeff metal nuclei (almost all metals have a Zeff of only +1 or +2 on valence electrons).

Tomorrow, we review for the biggest test of the year: Bonding and Intermolecular Forces.
Seriously, this test requires much more study and PRACTICE than any other test this year.
Be prepared. Take the practice quiz that I gave you at the end of class today. The quiz and explained answers are posted on Blackboard. If you have any problems, you really should come to extra help.
Extra help tomorrow morning in Room 301 at around 8AM! Be there.

Chem 8/9- we reviewed Van der Waal's/London Dispersion/induced dipole attractions and noted that, though they are relatively the weakest of intermolecular attractions, they can be stronger when molecules:
1. close together (under high pressure)
2. have a lot of electrons (so the induced dipoles are greater and more frequent)

We then explained the fact that all bonds must be significantly stronger (much harder to break) than mere intermolecular attractions because all bonds involve FULLY and oppositely charged particles whereas intermolecular attractions involve ONLY PARTIALLY and oppositely charged regions of different molecules attracting each other.

We looked at the four types of solids and we explained their respective properties.
IONIC: only conduct electricity (via mobile IONS) in the liquid or aqueous phase but NOT in the solid phase (ions NOT mobile in a SOLID). VERY high boiling and melting points due to the STRONG IONIC BONDS that require tremendous energy to OVERCOME.

NETWORK COVALENT: ONLY C (diamond or graphite), Si, SiC, and SiO2. There is no such thing as a single SiO2 molecule! The SiO2 tells you the RATIO of Si to O in the LATTICE of covalently bonded atoms.
No electrical conductivity = no ions and the electrons are NOT mobile; the electrons are stuck between the nuclei in bonds.
HIGH melting and boiling points because COVALENT BONDS are super STRONG and require insane quantities of energy to be broken.

MOLECULAR: e.g. solid H2O, C6H12O6, C12H22O11
solid molecules consist of COMPELETELY SEPARATE MOLECULES THAT ARE NOT BONDED TO EACH OTHER. The only thing holding the SEPARATE molecules frozen in place are INTERMOLECULAR attractions (Vanderwaal's, dipole-dipole, or H-"bonding" attractions).
So, relatively LOW to medium melting and boiling points.
NO electrical conductivity: NO ions and the electrons are stuck between the nuclei in bonds.

METALLIC: e.g. Cu, Ag, K, bronze
HIGH melting and boiling points due to STRONG metallic bonds- multiple positive nuclei attracted to any and all surrounding valence electrons of all surrounding atoms creates tremendous mutual attractions called metallic BONDS.
ELECTRICAL CONDUCTIVITY in both SOLID and LIQUID phases due to mobile ELECTRONS (not ions!), which are weakly attracted to any of the LOW Zeff metal nuclei (almost all metals have a Zeff of only +1 or +2 on valence electrons).

We then finished our conductivity lab and began to go over the write-up, which we will continue tomorrow as part of our review for Wednesday's exam.
Take the practice quiz that I gave you at the end of class today. The quiz and explained answers are posted on Blackboard. If you have any problems, you really should come to extra help.

Tomorrow, we review for the biggest test of the year: Bonding and Intermolecular Forces.
Seriously, this test requires much more study and PRACTICE than any other test this year.
Be prepared.
Extra help tomorrow morning in Room 301 at around 8AM! Be there.

Bio- we reviewed for Monday's exam. We got through the questions on the digestive system; the remaining questions and extensive answers, which are in your notes, are reproduced in a file on Blackboard. Write out those questions, answers, and drawings until you can do them by heart and you will be in great shape for Monday's exam.

Chem 7/8- we explained and illustrated the three types of INTERmolecular attractions and showed how to determine the intermolecular attractions that apply to a given molecule. The TWO factors that determine the type of intermolecular attractions between molecules of a given substance are:
1. the polarity of the bonds in the molecule and whether there are any lone pairs of electrons
2. the shape of the molecule, which determines how those bonds and/or lone pairs of electrons are arranged
The bottom line single criterion in determining molecular polarity is:
1. symmetric/even distribution or arrangement of electrons CAUSES a nonpolar molecule
2. asymmetric/uneven distribution or arrangement of electrons causes a polar molecule.

We then discussed ion-dipole (also called molecule-ion) attractions, which explain how aqueous solutions of salts form (see animation on Blackboard or drawing in notes).

We then began two discuss the four types of solid phase substances, which we will continue with on Monday:
1. ionic
2. covalent-network
3. molecular
4. metallic
We noted how the type of substance determines its properties i.e. electrical conductivity is only due to the NET movement of ions or electrons.

We then performed a lab procedure in which we tested the electrical conductivity of various substances in the solid phase, the liquid phase, or the aqueous phase. We will discuss this lab on Tuesday.

Chem 9- we explained and illustrated the three types of INTERmolecular attractions and showed how to determine the intermolecular attractions that apply to a given molecule. The TWO factors that determine the type of intermolecular attractions between molecules of a given substance are:
1. the polarity of the bonds in the molecule and whether there are any lone pairs of electrons
2. the shape of the molecule, which determines how those bonds and/or lone pairs of electrons are arranged
The bottom line single criterion in determining molecular polarity is:
1. symmetric/even distribution or arrangement of electrons CAUSES a nonpolar molecule
2. asymmetric/uneven distribution or arrangement of electrons causes a polar molecule.

We then discussed ion-dipole (also called molecule-ion) attractions, which explain how aqueous solutions of salts form (see animation on Blackboard or drawing in notes).

We then began two discuss the four types of solid phase substances, which we will continue with on Monday:
1. ionic
2. covalent-network
3. molecular
4. metallic
We noted how the type of substance determines its properties i.e. electrical conductivity is only due to the NET movement of ions or electrons.

Hey, scientists bring good news today to those of us (like me) who unduly fear needles
or IV devices; read on: http://www.sciencedaily.com/releases/2008/01/080107143001.htm

Bio- we discussed the functions of the rest of the endocrine system glands:
parathyroids- we drew out the negative feedback loop by which the parathyroids regulate the concentration of calcium ions in the blood.
adrenals- adrenaline is secreted when a person is under high stress from the environment (internal or external) so that the person can effectively fight or flee the situation.
adrenal glands also secrete hormones that regulate the concentration of water and sodium ions in the blood by targeting kidney cells.
We discussed the sex hormones secreted from the ovaries (females) and testes (males):
the menstrual cycle, involving the periodic thickening of the uterus and the maturation and release of an egg cell is regulated by pituitary hormones and ovary hormones (estrogen and progesterone); also, secondary sex characteristics develop as a result of the secretion of sex hormones: in females, breast development and skeletal changes such as the broadening of the pelvis occur; in males, testosterone causes more facial and body hair to grow and/or thicken, muscles to develop, the larynx to become thicker and more developed (deeper voice).

We then focused on the all-important negative feedback loop:
negative feedback is a key feature of the endocrine system that helps an organism maintain homeostasis. In general,
a deficiency of some substance "X" is monitored and detected by some gland "G"--> the gland then secretes a hormone "H" which targets specific cells which then are signaled to make more of substance "X" (increasing the level of substance "X" in the blood) so that there is no more deficiency; (now for the NEGATIVE feedback part) the normal/increased level of substance "X" in the blood causes gland "G" to STOP secreting hormone "H" (otherwise the level of substance "X" may get TOO HIGH!) thus completing the feedback loop and maintaining homeostasis.

Chem 7- I put up some practice test questions with answers on Blackboard. THIS UNIT requires MORE practice than ANY other unit in chemistry. You NEED to do as many problems as possible in order to be prepared for the exam on Wednesday.
we repeated that molecules that have a lone pair or pairs of electrons CAN FORM a coordinate covalent bond (with H+, for example) BUT any POLYATOMIC ION, like NH4+ or H3O+ already HAS a coordinate covalent bond!
We discussed how metal atoms bond to each other, which is called, naturally, metallic bonding.
Metal atoms have too few valence electrons to form an octet between two atoms so they mutually share their valence electrons in a lattice of positive metal nuclei. Each valence electron is only weakly attracted to any one nucleus (low Zeff) so the valence electrons are relatively free to flow throughout the lattice, which is why metals are good electrical conductors. All of the mutual attractions between all neighboring valence electrons and their neighboring positive nuclei make metallic bonds very strong.
We looked at the THREE different types of INTERmolecular attractions. BY DEFINITION, INTER means BETWEEN and molecular means molecules, so intermolecular attractions are NOT BONDS!!! They are merely the attractions BETWEEN the PARTIALLY positively charged side of one molecule and the PARTIALLY negatively charged side of a NEARBY separate molecule. There is NO sharing of electrons, there are NO fully charged IONS. End of story.
So,
(1) NONPOLAR MOLECULES can only form the weakest of intermolecular attractions (London Dispersion/Van der Waals/induced dipole) because any dipoles that form are random and short-lived.
(2) POLAR MOLECULES form stronger intermolecular attractions between their permanent dipoles ( attraction of the partial positive side of one molecule to the partial negative side of another molecule); these attractions are called DIPOLE-DIPOLE attractions.
(3) EXTREMELY POLAR MOLECULES:
Molecules that have H covalently bonded to F, O, or N are extremely polar. There is such unequal sharing of electrons between the (low electronegativity:2.1) H and the highly electronegative F,O, or N (4.0, 3.5, and 3.0) that the molecule has most of its electrons on ONE SIDE of the molecule (by F, O, or N) most of the time. Therefore, an EXTREME partial negative charge is permanently near the F, O, or N part of the molecule and an EXTREME partial positive charge is near the H part(s) of the molecule. So separate molecules will have EXTREME DIPOLE-DIPOLE attractions causing the molecules to stay near each other even at high avg KE (near room temperature). Classic examples of molecules that have these EXTREME DIPOLE-DIPOLE attractions that, confusingly, are called "hydrogen bonding" attractions (even though NO COVALENT BONDS EXIST BETWEEN ANY TWO DIFFERENT MOLECULES!) are H2O, NH3, and HF. Sorry, we just have to live with the name "hydrogen bonding" and make sure that we NEVER confuse it with a covalent bond WITHIN a molecule between H and another atom. In fact, any covalent bond between H and any other atom is about 500 times stronger than a "hydrogen bonding" attraction between separate molecules.

Chem 8/9- I put up some practice test questions with answers on Blackboard. THIS UNIT requires MORE practice than ANY other unit in chemistry. You NEED to do as many problems as possible in order to be prepared for the exam on Wednesday.
we repeated that molecules that have a lone pair or pairs of electrons CAN FORM a coordinate covalent bond (with H+, for example) BUT any POLYATOMIC ION, like NH4+ or H3O+ already HAS a coordinate covalent bond!
We discussed how metal atoms bond to each other, which is called, naturally, metallic bonding.
Metal atoms have too few valence electrons to form an octet between two atoms so they mutually share their valence electrons in a lattice of positive metal nuclei. Each valence electron is only weakly attracted to any one nucleus (low Zeff) so the valence electrons are relatively free to flow throughout the lattice, which is why metals are good electrical conductors. All of the mutual attractions between all neighboring valence electrons and their neighboring positive nuclei make metallic bonds very strong.
We looked at the THREE different types of INTERmolecular attractions. BY DEFINITION, INTER means BETWEEN and molecular means molecules, so intermolecular attractions are NOT BONDS!!! They are merely the attractions BETWEEN the PARTIALLY positively charged side of one molecule and the PARTIALLY negatively charged side of a NEARBY separate molecule. There is NO sharing of electrons, there are NO fully charged IONS. End of story.
So,
(1) NONPOLAR MOLECULES can only form the weakest of intermolecular attractions (London Dispersion/Van der Waals/induced dipole) because any dipoles that form are random and short-lived.
(2) POLAR MOLECULES form stronger intermolecular attractions between their permanent dipoles ( attraction of the partial positive side of one molecule to the partial negative side of another molecule); these attractions are called DIPOLE-DIPOLE attractions.
(3) EXTREMELY POLAR MOLECULES:
Molecules that have H covalently bonded to F, O, or N are extremely polar. There is such unequal sharing of electrons between the (low electronegativity:2.1) H and the highly electronegative F,O, or N (4.0, 3.5, and 3.0) that the molecule has most of its electrons on ONE SIDE of the molecule (by F, O, or N) most of the time. Therefore, an EXTREME partial negative charge is permanently near the F, O, or N part of the molecule and an EXTREME partial positive charge is near the H part(s) of the molecule. So separate molecules will have EXTREME DIPOLE-DIPOLE attractions causing the molecules to stay near each other even at high avg KE (near room temperature). Classic examples of molecules that have these EXTREME DIPOLE-DIPOLE attractions that, confusingly, are called "hydrogen bonding" attractions (even though NO COVALENT BONDS EXIST BETWEEN ANY TWO DIFFERENT MOLECULES!) are H2O, NH3, and HF. Sorry, we just have to live with the name "hydrogen bonding" and make sure that we NEVER confuse it with a covalent bond WITHIN a molecule between H and another atom. In fact, any covalent bond between H and any other atom is about 500 times stronger than a "hydrogen bonding" attraction between separate molecules.

Bio- Section 35.3 is due tomorrow; a two-page summary is acceptable.
we looked at the purpose and actions of the endocrine system, a system of glands that REGULATE/maintain homeostasis by causing relatively long-term or longer lasting changes (usually) in an organism as a result of signals/changes/cues from the environment (internal or external).
We saw that each gland secretes specific hormones directly into the bloodstream; each hormone can only bind to specific "target cells" that the hormone is made for. For example, insulin, secreted by the pancreas, can bind to specific cells in the liver because the protein receptors on those liver cells match the particular shape (lock and key) of the insulin hormone.

Once the hormone binds to the target cells, the target cells will produce particular chemicals or enzymes that helps the body to maintain homeostasis.

We saw that the pituitary gland, which is the master gland because it targets/controls all but one of the other endocrine glands, is directed/controlled by the hypothalamus. The hypothalamus is the nexus or connection between the nervous system, which is always sensing/monitoring the environmental changes of an organism, and the endocrine system.
The hypothalamus has many different cell receptors so it is able to monitor the levels of many of the body's key biochemicals and the hypothalamus will send a hormone/chemical signal to the pituitary if/when any of those biochemicals are in too high or too low a concentration.
The pituitary will then secrete the appropriate hormone so that the appropriate target cells/gland will secrete a substance to maintain homeostasis i.e. raise or lower the level of the deficient or excess chemical.
We then looked at the thyroid gland, which regulates the body's respiratory rate/metabolic rate.
The parathyroid glands, embedded in the four corners of the thyroid gland, regulate the level of calcium ions in the blood and bones.
We also began to discuss the all IMPORTANT concept of negative FEEDBACK, which is THE key feature of maintaining homeostasis.
For example, if the level of calcium ions in the blood is too low, the parathyroid glands will secrete a hormone (parathormone) that targets the BONE CELLS to release some of their stored calcium ions into the blood, thus RAISING the level of calcium ions back to a normal level. Once the normal level of calcium ions is back to normal (this is the "feedback" part!), that normal level of calcium ions in the blood CAUSES the parathyroid glands to STOP secreting its hormone (parathormone). That completes the feedback cycle and calcium homeostasis is maintained.

Chem 7- we learned how to determine whether a molecule that contains POLAR covalent BONDS is overall a POLAR MOLECULE (asymmetric/uneven distribution of charge) or a NONPOLAR molecule (symmetric/even distribution of charge). So, a molecule with polar bonds may be polar or nonpolar DEPENDING on what the particular electron and/or molecular geometry of the molecule is. This geometry can be determined by drawing the correct Lewis structure and seeing how many regions of electrons are around the central atom.

We then looked at one of the covalent bonds that is formed when a polyatomic ion forms: the COORDINATE COVALENT bond. This bond is the same as any covalent bond EXCEPT that BOTH of the electrons that are shared in the bond originally come from ONLY ONE of the two atoms that are bonded. We saw that NH4 + and H3O + contain one coordinate covalent bond each. In order for a molecule to be ABLE to FORM a coordinate covalent bond, it has to already have a NONBONDED, LONE pair of electrons that it can share with an H+ ion or some other particle that has an empty valence orbital.

We then finished up our molecular models lab; you can hand that in on Friday.

Chem 9- we learned how to determine whether a molecule that contains POLAR covalent BONDS is overall a POLAR MOLECULE (asymmetric/uneven distribution of charge) or a NONPOLAR molecule (symmetric/even distribution of charge). So, a molecule with polar bonds may be polar or nonpolar DEPENDING on what the particular electron and/or molecular geometry of the molecule is. This geometry can be determined by drawing the correct Lewis structure and seeing how many regions of electrons are around the central atom.

We then looked at one of the covalent bonds that is formed when a polyatomic ion forms: the COORDINATE COVALENT bond. This bond is the same as any covalent bond EXCEPT that BOTH of the electrons that are shared in the bond originally come from ONLY ONE of the two atoms that are bonded. We saw that NH4 + and H3O + contain one coordinate covalent bond each. In order for a molecule to be ABLE to FORM a coordinate covalent bond, it has to already have a NONBONDED, LONE pair of electrons that it can share with an H+ ion or some other particle that has an empty valence orbital.

Bio- HW: if you didn't hand in text 35.2 outline today, do so tomorrow (full credit). Text section 35.3 is due on Thursday; I can return that to you by Friday so that you can study your three outlines over the weekend.
Today, we finished up the digestive system. We noted the types of macronutrients (proteins, carbohydrates, fats, and water) and their purpose in the body. We then looked at micronutrients (vitamins and minerals), which are needed in small quantities daily, and their purpose in the body. On Blackboard, in addition to the worksheet from today, I posted some more digestive system worksheets with answer keys.
We introduced the system that regulates/maintains homeostasis in the body even in a changing environment: the endocrine system.
The endocrine system is a system of 9 glands: hypothalamus, pituitary, pineal, thymus, thyroid, parathyroid, adrenal, islets of Langerhans (of the pancreas), testes (male), ovaries (female).
These glands secrete substances DIRECTLY into the bloodstream for quick circulation throughout the body, HOWEVER, only one SPECIFIC group of "target cells" can bind to a given specific hormone. The target cells will then produce a substance or substances that will help the body maintain homeostasis. The glands are then signalled to stop secreting the hormone once homeostasis is reached (this is known as a negative feedback loop).

Chem 7: we revisited molecular geometry based on our Lewis dot structures and the repulsions among the electron pairs (bonding and nonbonding) around the central atom.
We then got to the POINT of figuring out molecular geometry, which is to determine whether a molecule overall is POLAR (has a definite partial positive side and a definite partial negative side) or NONPOLAR (due to even/symmetric distribution/spread of charge/electrons).

There are three possibilities:
Case 1: If all of the bonds of a molecule are nonpolar, then the molecule MUST BE NONPOLAR due to the equal sharing and distribution of electrons in the molecule.

Case 2a: If the bonds in the molecule are polar, then the molecule is usually also POLAR

EXCEPT!!!!:

Case 2b: if the polar bonds are evenly/symmetrically arranged e.g. as in a CO2 molecule.

Case 2b is THE REASON why you must be able to reason the molecular geometry of a molecule from its Lewis structure. Cases 1 and 2a are pretty intuitive and easy to remember.

We then discussed the weak, temporary intermolecular attractions that can form between nonpolar molecules. These are due to the random motion of electrons within their orbitals that sometimes results in a temporarily uneven distribution of charge/electrons. A temporary partial negative and partial positive pole develops in the molecule which CAUSES other dipoles to form in nearby molecules. Then, these temporarily dipole molecules attract each other (partial positive side of one molecule to the partial negative side of the next molecule) and may stick together (form a liquid) if the molecules are moving slow enough (at a cold enough temperature). That is how, at low temperature or at high pressure, nonpolar molecules that are normally gases at room temperature can liquefy.

We will discuss the relatively stronger attractions among polar molecules.

Chem 8/9:we revisited molecular geometry based on our Lewis dot structures and the repulsions among the electron pairs (bonding and nonbonding) around the central atom.
We then got to the POINT of figuring out molecular geometry, which is to determine whether a molecule overall is POLAR (has a definite partial positive side and a definite partial negative side) or NONPOLAR (due to even/symmetric distribution/spread of charge/electrons).

There are three possibilities:
Case 1: If all of the bonds of a molecule are nonpolar, then the molecule MUST BE NONPOLAR due to the equal sharing and distribution of electrons in the molecule.

Case 2a: If the bonds in the molecule are polar, then the molecule is usually also POLAR

EXCEPT!!!!:

Case 2b: if the polar bonds are evenly/symmetrically arranged e.g. as in a CO2 molecule.

Case 2b is THE REASON why you must be able to reason the molecular geometry of a molecule from its Lewis structure. Cases 1 and 2a are pretty intuitive and easy to remember.

We then discussed the weak, temporary intermolecular attractions that can form between nonpolar molecules. These are due to the random motion of electrons within their orbitals that sometimes results in a temporarily uneven distribution of charge/electrons. A temporary partial negative and partial positive pole develops in the molecule which CAUSES other dipoles to form in nearby molecules. Then, these temporarily dipole molecules attract each other (partial positive side of one molecule to the partial negative side of the next molecule) and may stick together (form a liquid) if the molecules are moving slow enough (at a cold enough temperature). That is how, at low temperature or at high pressure, nonpolar molecules that are normally gases at room temperature can liquefy.

Polar molecules, which each have a permanent partial (+) and a partial (-) side, form relatively stronger attractions among each other; therefore, even at room temperature, polar molecules are typically liquids or solids.

Bio- tomorrow, the outline to the text section 35.2 is due.
Today we discussed the disorders/diseases/failure to maintain homeostasis of the digestive system.
We looked at such maladies as constipation (too much water reabsorbed by the colon), diarrhea (too little water reabsorbed by the colon along with rapid peristalsis and movement of undigested food), appendicitis, and gall stones.
We then looked at the life process of nutrition in general; there are two main types of nutrition among organisms: autotrophic (plants and algae make their own food via photosynthesis and then digest their own food) and heterotrophic (organisms that must ingest and digest other organisms for nutrition).
We saw that bacteria and fungi have adaptations for nutrition by which they secrete enzymes EXTRACELLULARLY to digest food particles outside of their cells; then, the products of digestion: glucose, amino acids, nuclei acids, and fatty acids, are absorbed via diffusion into the bacteria or fungi.
Amoeba use their cell membranes to form pseudopods to engulf/ perform phagocytosis on food particles in their surrounding; then, the amoeba digests the food intracellularly. Paramecia sweep food into their oral grooves and then digest the food intracellularly.
We then looked at various nutrients that are ingested for survival:
fats, proteins, lipids, nucleic acids, vitamins, minerals, and water (see video on Blackboard).

Chem 7/8: we looked at the four main molecular geometries: linear, bent, trigonal pyramidal, and tetrahedral, and saw that all molecular geometries are caused by the electron pair repulsions around the central atom. So electron geometry causes molecular geometry.
We then practiced reasoning from Lewis structures to molecular geometry.
Do the related problems in the hw packet and I will post some more worksheets with solutions on Blackboard soon.
We then began our molecular model lab which shows you, in 3-D, how the shape of a molecule can be determined from its Lewis Dot structure.

Chem 9: we looked at the four main molecular geometries: linear, bent, trigonal pyramidal, and tetrahedral, and saw that all molecular geometries are caused by the electron pair repulsions around the central atom. So electron geometry causes molecular geometry.
We then practiced reasoning from Lewis structures to molecular geometry.
Do the related problems in the hw packet and I will post some more worksheets with solutions on Blackboard soon.

Bio- HW due Tuesday- text outline of section 35.2
we continued our journey through the human digestive system, focusing on the extensive surface area of the lining of the small intestine. The finger-like projections, villi, are evolutionary adaptations (provide for human survival) because they maximize the surface area of the small intestine, which maximizes the amount of nutrients absorbed. The proteins, carbs, lipids, and nucleic acids get totally broken down to their respective building block/simple molecules. Secretions of juices from the liver (bile) and the pancreas (various proteases and lipases) aid the small intestine in its complete digestion of nutrients.
Peristalsis of the smooth muscular lining of the small intestine pushes the undigested food and fiber to the colon.
We emphasized the main purpose of the colon: to reabsorb water that has been used in digesting food; mucous, saliva, etc. are mostly water, which must not be lost, otherwise dehydration would occur.
We then saw that the undigested food and fiber, as well as a lot of bacteria that live in the colon, are then stored in the rectum and then pushed out via the voluntary striated muscles of the anus.
Next week, we will discuss general nutrition and then the system that regulates your body: the endocrine system.

Chem 7: we finished our discussion of polar vs. nonpolar covalent bonds between nonmetal atoms of molecules. We learned that, when there is an electronegativity difference of 0.6 or greater between the two bonding atoms, electrons are not equally shared and the more electronegative atom develops a PARTIAL negative charge.
We then learned the SIX step process to properly draw the Lewis structure of a molecule. You MUST practice this method exactly as taught or else you will make costly errors for the rest of the course. Drawing Lewis structures properly is one of the most practical and important skills in chemistry.
We will get some more practice with this during the molecular models lab.
You should start your homework packet this weekend.

Chem 8/9: we focused on polar vs. nonpolar covalent bonds between nonmetal atoms of molecules. We learned that, when there is an electronegativity difference of 0.6 or greater between the two bonding atoms, electrons are not equally shared and the more electronegative atom develops a PARTIAL negative charge.
We then learned the SIX step process to properly draw the Lewis structure of a molecule. You MUST practice this method exactly as taught or else you will make costly errors for the rest of the course. Drawing Lewis structures properly is one of the most practical and important skills in chemistry.
We then applied this skill in the molecular models lab, which we will continue on Monday. As you saw, in order to deduce the 3-D structure of a molecule, you must first know how to draw its Lewis structure, which shows you where the electrons are shared about the central atom.
You should start your homework packet this weekend.
We will get some more practice with this during the molecular models lab.